Project meeting of STEP at the site of the company ATS - Agro Trading & Solutions in Hardegsen (Photo: DBFZ)

sector coupling | CHP Power Biogas System integration

Project ID 03EI5409

ProPhaSep - Flexibilisation of biogas production through process phase separation and thin slurry recirculation

Schematic diagram of a biogas plant with double thin sludge recirculation (source: TUB)


  • 01.01.2020 – 30.06.2022


Technical University Berlin
Chair of Bioprocess Engineering
Ackerstraße 76
13355 Berlin

Prof. Peter Neubauer – project leader
Telephone: +49 (0)30314 72269
E-mail: peter.neubauer‍@‍

Dr. Anja Lemoine – direct contact person
Telephone: +49 (0)30 314 72527

Dr. Stefan Junne – further contact person
Telephone: +49 (0)30 314 72527
E-mail: stefan.junne‍@‍


03EI5409B - Kurt-Schwabe-Institut für Mess- und Sensortechnik e. V.
03EI5409C - FWE GmbH
  • Address:
  • FWE GmbH
    Wölsauer Straße 20
    95615 Marktredwitz
  • Contact:
  • Pierre Haider – project leader
    Telephone: +49 (0)9231 50242

Associated partners

Cooperation partners



Planned results:

  • Plant level: process, pilot plant
  • Concept level: plant concept
  • Data level: method
  • Market level: market forecasts, patents
  • Publications: guides, manuals, scientific papers


The plant operation should be made more flexible with regard to substrate provision, energy generation and the use of side products by a stronger separation of the process phases within the configuration of stirred tank reactors prevailing in existing plants. For this purpose, a thin sludge recirculation should be installed between the main fermenter and the post-fermenter. A second thin sludge recirculation after the post-fermenter should stabilize the methanogenesis. The recirculations are controlled with the help of an optimized online measurement technology for dissolved hydrogen and dissolved methane.


The aim of the project is to enhance monitoring strategies and to achieve an economic flexibility of plant operation on the bioprocess side within the biogas plant stock for easier system integration. In addition, the process is to be optimized separately by different operating conditions in both fermenters and the robustness towards substrates which are difficult to hydrolyze, such as many residual and waste materials, is to be increased.



  • Establishment of a plant for phase separation with variable positions for thin sludge recirculation in a stirred tank cascade in continuous culture (hydrolytic, acidogenic and acetogenic phase in the first reactor, methanogenesis in the second reactor)

  • The hydrogen partial pressor is used as a control variable for the regulation of thin sludge recirculation


  • Further development of the extractive measuring method for the online determination of dissolved gases in biogas media in order to optimize the following parameters: reliability in practical use, miniaturisation of the components, optimization of the control and integration into existing process control systems and a significant reduction in the use of process media such as purified carrier gas
  • Adaptation of prototypes of the measuring system to laboratory and, if necessary, also to practical systems for initial tests


  • Design of the process control and integration into the existing process control system
  • Demonstration of the functionality
  • Accompaniment of the development of recycling concepts



  • Process technology
  • Microbiology


  • Measurement- and control technique


  • Plant manufacturer
  • Consulting


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